Guide to Horse Diseases: Symptoms and Treatments.


sick horse

Some of the most common horse diseases, that horses are susceptible to, are preventable with the proper horse vaccines

This is why it is so important to keep up with you vaccination schedule.

Planning a good vaccination program for your horse is a very important factor when owning horses. Equine diseases can cause loss of use or even death for a horse.

If your horses are like mine, they bec
ome family members. I can not imagine the guilt that I would feel if my horse became ill or died, because of something that I neglected to do.

The following is a list of the most common horse diseases and their symptoms:
Tetanus(lockjaw) – is a bacteria that enters the body at the sight of a wound or the umbilical cord stump in a foal. Its symptoms are early signs of colic and stiffness. Horses will develop spasms in the jaw, neck, hind legs and muscles around the wound.

If this disease goes untreated, as it worsens, the horse will develop labored breathing. Stiffness develops in the front and hind legs.

The tail is held out stiffly, ears are erect and nostrils will be flared. The jaws will contract so that the horse is unable to open his mouth. In the final stage, the horse will lie down and die of respiratory paralysis.

Treatment: The wound must be opened widely, removing all infected tissue. It must be washed thoroughly and penicillin injected into the wound. Wounds must be left open to allow for drainage.

Prevention: Thoroughly clean and treat all new wounds. This will prevent most cases of tetanus. Foals should be given a tetanus shot when they are born.

Eastern(EEE)/Western(WEE) and Venezuelan Equine Encephalitis(VEE)

These are the top 3 mosquito transmitted horse diseases. They attack the central nervous system of horses.

EEE is the most dangerous, with a mortality rate of 70 to 90 percent. WEE is the least dangerous of the 3, its mortality rate is about 20 to 50 percent.

The first signs of these diseases are a high fever which may last for 2 or 3 days. Brain inflammation will start to occur. Signs of brain inflammation are compulsive walking, loss of coordination and apparent blindness.

As the disease progresses, the horse becomes extremely lethargic and seemingly oblivious to his surroundings. This stage is referred to as “sleeping sickness”.

As it starts to affect the spinal cord, the horse will develop a staggering gait, weakness and muscle twitching.

The final stage is paralysis. The horse will develop seizures and will collapse, unable to breath.

Call your vet immediately if you suspect your horse has this disease. Intensive treatment is critical for a successful outcome.

West Nile Virus(WNV) is a mosquito-borne virus that causes encephalitis(inflammation of the brain) and/or meningitis (inflammation of the lining of the brain and spinal cord).

Typical signs include muscle trembling, skin twitching, ataxia (uncoordination, stumbling, limb weakness) that appears suddenly.

In some cases it appears gradually and worsens. Sleepiness, dullness, listlessness, facial paralysis (droopy eyelids, lower lip), difficulty with urination and defecation, and an inability to rise are also signs. Some horses may develop mild fevers, blindness and seizures.

There is currently no vaccine for humans, but there is a vaccine for horses. Giving your horse the proper vaccinations will prevent this disease.

Rabies – Is transmitted through a bite from an infected animal. It is a highly fatal infection of the central nervous system. Its symptoms include, increased saliva, excitability, disorientation and running blindly.

Equine Influenza – an upper respiratory disease that is similar to the flu in humans. Its symptoms are a nasal discharge, cough, fever and loss of appetite.

Treatment: Isolate this horse from the rest of the herd. Stall rest is very important. Butazolidin is used to control fever and muscle stiffness.

Potomac Horse Fever – is a diarrheal disease that is infrequently seen in the western U.S. Horses with symptoms will develop high fever, lethargy, of appetite and diarrhea. The stool is very watery and abundant.

COPD – Chronic Obstructive Pulmonary Disease in horses (also known as Heeves) is a lung disease that is like asthma in humans. It is more common in colder climates where horses are stalled most of the time in the winter months. It is usually found in horses 7 years and older. It is rare in warmer climates where horses are pastured most of the time.

Some of the symptoms of this disease are coughing or heeving to expel air and dust particles from the lungs. Coughing, weight loss and lack of energy are usually good indicators.

To prevent Chronic Obstructive Pulmonary Disease in horses, turn horses out as much as possible. Keep the stall and barn area free of dust and mold and never use dusty or moldy hay. Use rubber mats or shredded paper in stalls instead of shavings or straw.

Strangles – Strangles disease in horses is a highly contagious horse disease that can spread rapidly throughout a herd.
Symptoms can range from very mild to severe. These include, swelling of the lymph nodes under the jaw, nasal discharge, fever, fast breathing and lethargy.

When the lymph nodes swell, they will often abcess and drain.

After dealing with a horse who has strangles, always wash your hands thoroughly before touching another horse.

Equine Herpes Virus/Rhinopneumonitis – is a serious respitory disease in young horses, ages two and under. It is highly contagious and can spread rapidly throughout a herd.

The herpes virus can cause late abortions in pregnant mares. Its symptoms are nasal discharge, cough and fever. However it is not fatal to most horses.

Equine Infectious Anemia(Swamp fever) – This is more often than not, a fatal horse disease. It is very contagious and is transmitted by blood sucking insects, such as horseflies and mosquitoes.

Symptoms include rapid weight loss, fever, sweating, weakness, anemia, and swelling of the limbs. The mortality rate is very high, sometimes sudden death is the first indication.

Coggins test detects the presence of Equine Infectious Anemia. All horses that travel into the U.S. are required to have a negative Coggins test.

Once your horse has tested negative, your vet will give you a signed paper which states that your horse is negative. This document, (or a copy) should be carried with the horse wherever he travels. You should also make this a requirement before introducing any new horse into your barn.

Equine Viral Arteritis – an acute respiratory illness similar to influenza. Typically, fluid will accumulate in the hind limbs, sheath, scrotum and abdominal wall. Other signs of this horse disease include loss of appetite, dehydration, colic and diarrhea.

Cushing’s Disease is a disease of the endocrine system and there is no cure. With daily medication to control symptoms, most horses can lead a somewhat normal life.

This disease normally occurs in ponies and older horses, however it has been known to happen in younger horses.

Cushing’s is caused by a tumor on the pituitary gland. The tumor causes the gland to produce excessive amounts of the hormone, cortisol.

Symptoms of Cushing’s Disease


  • Long, wavy haircoat, that does not shed in the spring.
  • Excessive water intake
  • Increased appetite
  • Weight loss, despite the decreased appetite
  • Increased urination
  • Will have more bouts with laminitis

You can help your horse to better deal with this horse ailment by keeping his stress level to a minimum. Clipping the long hair will help to keep him comfortable, and keeping him on a easily digestable diet.

Botulism – This disease can affect all warm blooded animals, but horses are especially sensitive to it.

It is caused by a bacterial organism called clostridium botulinum, that produces a toxin or poison. This toxin is the most potent toxin in the world.

It affects the nervous system by interrupting nerve transmission to the muscles, causing paralysis.



Source of this article :

Image of sick horse used with permission :


For a list of tick transmitted diseases,  uncommon and rare horse diseases follow this link to the entire article.